#include <bits/stdc++.h>
using namespace std;
typedef pair<int64_t,int64_t> ii;
int64_t k,n,Count=1;
ii tree1[200005],tree2[200005];
vector<int64_t> V,VV,mind,maxd,g[200005];
vector<ii> gg[200005];
map<int64_t,int64_t> F;
void Update1(int64_t idx,int64_t data)
{
while(idx<=Count)
{
tree1[idx].first+=data;
tree1[idx].second++;
idx+=idx&-idx;
}
}
ii Query1(int64_t idx)
{
ii rs=ii(0,0);
while(idx>0)
{
rs.first+=tree1[idx].first;
rs.second+=tree1[idx].second;
idx-=idx&-idx;
}
return rs;
}
void Update2(int64_t idx,int64_t data)
{
while(idx>0)
{
tree2[idx].first+=data;
tree2[idx].second++;
idx-=idx&-idx;
}
}
ii Query2(int64_t idx)
{
ii rs=ii(0,0);
while(idx<=Count)
{
rs.first+=tree2[idx].first;
rs.second+=tree2[idx].second;
idx+=idx&-idx;
}
return rs;
}
void Sub1()
{
char c1,c2;
int64_t t1,t2,sum=0;
for(int64_t i=1;i<=n;i++)
{
cin>>c1>>t1>>c2>>t2;
if(c1==c2)
sum+=abs(t1-t2);
else
{
V.push_back(t1);
V.push_back(t2);
mind.push_back(min(t1,t2));
maxd.push_back(max(t1,t2));
sum+=abs(t1-t2)+1;
}
}
if(V.size()==0)
{
cout<<sum;
return;
}
sort(V.begin(),V.end());
F[V[0]]=1;
for(int64_t i=1;i<V.size();i++)
if(V[i]>V[i-1])
F[V[i]]=++Count;
for(int64_t i=0;i<mind.size();i++)
Update2(F[mind[i]],mind[i]);
for(int64_t i=0;i<maxd.size();i++)
Update1(F[maxd[i]],maxd[i]);
int64_t res=1e18;
for(int64_t i=0;i<V.size();i++)
{
ii t1=Query1(F[V[i]]-1);
ii t2=Query2(F[V[i]]+1);
res=min(res,sum+2*(V[i]*t1.second-t1.first+t2.first-V[i]*t2.second));
}
cout<<res;
}
void Sub2()
{
char c1,c2;
int64_t t1,t2,sum=0;
for(int64_t i=1;i<=n;i++)
{
cin>>c1>>t1>>c2>>t2;
if(c1==c2)
sum+=abs(t1-t2);
else
{
V.push_back(t1);
V.push_back(t2);
mind.push_back(min(t1,t2));
maxd.push_back(max(t1,t2));
sum+=abs(t1-t2)+1;
}
}
if(V.size()==0)
{
cout<<sum;
return;
}
sort(V.begin(),V.end());
F[V[0]]=1;
VV.push_back(V[0]);
for(int64_t i=1;i<V.size();i++)
if(V[i]>V[i-1])
{
F[V[i]]=++Count;
VV.push_back(V[i]);
}
V=VV;
for(int64_t i=0;i<mind.size();i++)
g[F[maxd[i]]].push_back(mind[i]);
for(int64_t i=0;i<mind.size();i++)
Update2(F[mind[i]],mind[i]);
for(int64_t i=0;i<maxd.size();i++)
Update1(F[maxd[i]],maxd[i]);
int64_t res=1e18;
for(int64_t i=0;i<V.size();i++)
{
ii t1=Query1(F[V[i]]-1);
for(int64_t j=i;j<V.size();j++)
gg[j].clear();
int64_t C=0,S1=0,S2=0;
for(int64_t j=i;j<V.size();j++)
{
if(j>i)
S1+=C*(V[j]-V[j-1]);
int64_t jj=F[V[j]];
for(int64_t t=0;t<g[jj].size();t++)
if(g[jj][t]>=V[i])
{
int64_t rs=-1,l=jj+1,r=V.size()-1;
while(l<=r)
{
int64_t mid=(l+r)/2;
if(g[jj][t]-V[i]<V[mid]-V[j])
{
rs=mid;
r=mid-1;
}
else
l=mid+1;
}
if(rs!=-1)
gg[rs].push_back(ii(g[jj][t],V[j]));
C++;
}
for(int64_t t=0;t<gg[jj].size();t++)
{
S1-=V[j]-gg[jj][t].second;
C--;
S2+=gg[jj][t].first-V[i];
}
ii t2=Query2(F[V[j]]+1);
res=min(res,sum+2*(V[i]*t1.second-t1.first+t2.first-V[i]*t2.second+S1+S2));
}
}
cout<<res;
}
int main()
{
ios_base::sync_with_stdio(false);
//freopen("TEST.INP","r",stdin);
cin>>k>>n;
if(k==1)
Sub1();
else
Sub2();
}
